Filter Threads By Thread Prefix - MyBB 1.6 Only

[leefish]

And back on thread prefixes - I was looking in the old posts and I found this:

http://mybbhacks.zingaburga.com/showthread.php?tid=57  - its a thread about having custom smilies images - per theme. Of course I thought oooh, maybe we can do this for thread prefixes too.

But its not really the same. I did try using a theme image like RateU did for forums  in this thread, but I could not get to work.
http://mybbhacks.zingaburga.com/showthread.php?tid=448

I'm not sure if its the idea that is flawed or the execution by me, but it would be neat. Any suggestions?